DIP 1017--Add Bottom Type--Community Review Round 1

[Timon Gehr]

On 09.08.2018 05:02, Mike Parker wrote:
> This is the feedback thread for the first round of Community Review for 
> DIP 1017, "Add Bottom Type":
> 
> https://github.com/dlang/DIPs/blob/8274b0f600075e4553b41c31f4b77be2d917bb40/DIPs/DIP1017.md 
> 
> 
> All review-related feedback on and discussion of the DIP should occur in 
> this thread. The review period will end at 11:59 PM ET on August 24, or 
> when I make a post declaring it complete.
> 
> At the end of Round 1, if further review is deemed necessary, the DIP 
> will be scheduled for another round. Otherwise, it will be queued for 
> the Final Review and Formal Assessment by the language maintainers.
> 
> Please familiarize yourself with the documentation for the Community 
> Review before participating.
> 
> https://github.com/dlang/DIPs/blob/master/PROCEDURE.md#community-review
> 
> Thanks in advance to all who participate.

Copy-paste of my comment on the DIP pull request:

"`Tbottom* → Tbottom` and `Tbottom[] → Tbottom` seem a bit unprincipled. 
I'd have rather expected to see `Tbottom* == typeof(null)` and 
`Tbottom[] == typeof([])`. In general, I'd advise against having special 
rules with regards to type construction, as special behavior like this 
can harm generic code."

I think if we in fact want to have some sort of "bottom propagation" 
nonetheless, it should be expression-based, not type-based.